In the Keystone Driller Co. v. Northwest Engineering Corp., 1934, the U.S Supreme Court ruled in favor of Northwest Engineering Corp., stating that Keystone Driller Co.'s patent was unenforceable due to "unclean hands." The case revolved around a dispute over patents for machinery used in oil drilling operations. Keystone had obtained an injunction against Northwest based on three patents they held, but it was revealed during litigation that one of these patents had been procured through fraudulent means - specifically by bribing a witness and suppressing evidence during its application process. This misconduct led to the doctrine of "unclean hands," which states that a party who is asking for equitable relief must be free from wrongdoing or unfair conduct relating to the subject matter of his/her claim. Therefore, even though two out of three patents were validly owned by Keystone, their unethical behavior regarding one patent invalidated their entire claim.

In the dissenting opinion for Keystone Driller Co. v. Northwest Engineering Corp., Justice Stone argued that the majority's decision to invalidate a patent due to misconduct was too broad and could potentially lead to unjust outcomes in future cases. He contended that while fraud or deceit should indeed be grounds for invalidating a patent, it should only apply when such behavior directly affects the procurement of the patent itself - not when it is related to other aspects of litigation surrounding said patent. In this case, he believed that although there was evidence of wrongdoing on part of Keystone Driller Co., this did not necessarily mean their patents were obtained dishonestly or undeservedly. Therefore, he disagreed with voiding these patents based solely on unrelated unethical actions by the company.